Question

find the circumference of the circle whose diameter is 63cm

Answer 1

Forumla is the same C = 2piR. In this case R equals 63 cm and pi is 3.14 as always. So 2 x 63 = 126. 126 x 3.14 is 395.64 cm.

Answer 2

$\bf \textit{circumference of a circle}\\\\ C=\pi d~~ \begin{cases} d=diameter\\ \hrulefill\\ d=63 \end{cases}\implies C=63\pi \implies C\approx 197.920337176$